Excavator tooth driving apparatus



United States Patent lnventor John D. Bennett Richardson, Texas Appl. No. 742,599

Filed July 5, 1968 Patented Nov. 17, 1970 Assignee Sun Oil Company Philadelphia, Pennsylvania a corporation of New Jersey EXCAVATOR TOOTH DRIVING APPARATUS Primary Examiner-Ernest R. Purser AttorneysGeorge L. Church, Donald R. Johnson, Wilmer E.

McCorquodale, Jr. and John E, Holder ABSTRACT: The particular embodiments described herein as illustrative of one form of the invention utilize, in earth excavating equipment, apparatus for preventing breakage of excavator teeth when hard materials are encountered and apparatus for imparting a jarring force to the excavator in order to break or dislodge unusually hard material within the material being excavated.

8 Claims, 6 Drawing Figs.

US. Cl 299/67, 37/142, 172/5, 172/777, 299/70 Int. Cl E02f 9/28 Field of Search 299/67, 69, 70; 175/297; 37/142, 189, 190; 173/15; 172/5, 777

Sheet: 2 of 2 INVENTOR JOHN D. BENNETT W Lfl L IIFIIL v Patented Nov. 11, 1970 km mm m 3 mm x. S

. ATTORNEY 1 EXCAVATOR TooTII DRIVI G APPARATUS BACKGROUND THE INvENTIoN This invention relates to an apparatus for excavating earth materials and more particularly, to an apparatus for excavating hard materials from earth formations.

A problem associated with the excavating or mining of earth materials is the wear and breakage of earth contacting portions of excavating equipment, which, for example, may be in sands. The sands are composed 'of a silicous material, generally having a size greater. than that passing a 325 mesh screen, saturated with a relatively heavy, viscous bitumin in quantities of from to '2I weight percent of the total composition. The bitumin is quite viscous and contains typically 4:5 percent sulfur, and 38 percent aromatics A specific gravity at 60 percent F., ranges typically from about I to about 1.06. The tar sands also contain clay and silt in quantities from l to 50 weight percent of the total composition. Silt is normally defined as mineral which passes a 325 mesh screen, but which It is therefore an object of the present invention to provide a new and improved apparatus for excavating materials containing hard substances.

SUMMARY or THE INVENTION The present invention contemplates an excavator in the form of a shovel or a bucket wheel, which has a set of teeth for digging'the material'to be mined. Means are provided on the the form of bucket teeth. Wear isnormally the result of abrasion and impact with earth materials being excavated. An example of this problem involves the mining of bituminous tar.

is larger than 2 microns. Clay is mineral smaller than 2' microns, including some silicous material of that size. The composition described, together with the peculiar consistency due to its viscous nature, has been found to exhibit extreme wear properties on equipment normally used for excavating earth materials. Therefore it is desirable, in the design of such equipment, to use materials which exhibit good wear properties in such an environment. However, layers of hard rock material are often encountered in the formations containing the tar sands. Also, boulders or large rock masses are found embedded in the tar sands. Due to the encountering of such hard materials, it is costly to use some materials in the construction of excavating equipment which might otherwise, be applicable, because of their wear properties. For example, tungsten carbide bucket teeth exhibit desirable wear properties for excavating the abrasive tar sand material, but are not compatible with the excavation of hard rock, because of the brittle nature of tungsten carbide.

The present invention is there'foredirected to an apparatus I for mining earth materials, and in particular tar sands under the conditions described above. In its most specific embodiment, the invention is disclosed with a bucket wheel excavator for mining the tar sands; However, the apparatus disclosed would have application to a variety of excavating techniques employed with a variety of earth materials. Regardless of the particular excavating .apparatus utilized for mining earth materials, continuous contact between an excavating member and earth materials causes a great deal of wear on the members. It is proposed by the present invention to reduce this wear, and to'provide a means for breaking up hard layers of materials encountered within the particular material being excavated. In mining tar sands, as with other materials, the excavator bucket is often mounted on a Wheel, with the wheel hard. When lenses of hard formation or boulders are encountered, often times the wheel cannot be stopped in time to prevent the teeth from breaking, which in turn causes a shutdown of. the excavator for the purpose of replacing the teeth. Such a shutdown ofthe excavator is extremely expensive. Some idea of theexpense is obtained by considering the size of a bucket wheel excavator, which for example, is being used in the mining of tar sands/These particular excavators are 100 feet high from the bottom treads of their caterpillar crawlers to the top of their bucket wheel riggings. They are about 210 feet in length and weigh about 1700 tons each.

bucket for imparting a jarring blow to the hard materials when they are encountered. In oneembodiment of the invention, the teeth themselves are comprised of, generally speaking, two different types for'digging earth materials exhibiting dissimilar physical properties. One of the types of teeth is constructed of a wear resistant material and has a resilient means located beneath the tooth, The second type of teeth, which are recessed downwardly fromthe first resiliently mounted teeth,

are nonmovably mounted within the excavator housing, and

are preferably made of adifferent materiaLbai/ing properties which are more compatible with the harder'material being mined. This'nrrangement permits the first type of teeth to recess when hard materials are encountered with the stationary teeth carrying the load.

In another embodiment of the invention, one or more teeth include-in their structure, a jarring device which permits a controlled recession of the tooth, a prcdetermined amount, whereupon a mechanism permits fast release or recession of the tooth until it is impacted by a hammer. This release system has provisions for fast resetting, so that the jarring control mechanism is rapidly restored to its initial condition for subsequent operations.

Another embodiment of the invention utilizes a mechanical I or hydraulic jarring mechanism to impart a jarring force to the entire bucket in response to a greater than normal loud being applied to the bucket.

A complete understanding of this invention may be had by reference to the following detailed description, when read in conjunction with the accompanying drawings illustrating embodiments thereof.

BRIEFDESCRIPTION OF THE DRAWINGS DESCRIPTION or THE PREFERRED EMBODIMENTS Referring to the drawings, FIG. I shows a side view of an excavator wheel 12 mounted on a boom 14. This structure forms a part'of an excavator apparatus, the remainder of which is not shown for the sake of simplicity. However, such apparatus normally would consist of a support structure adapted to .rest

on the ground, a turntable structure having a turning axis, and rotatably supportedby the'support structure, the working boom [4 connected at one end of the turntable structure and projecting outwardly therefrom, and the bucket wheel 12 which is rotatably-mounted at one end of the working boom 14. The support structure is normally mounted on wheels or tracks for moving the structure relative to the material being excavated. The apparatus also may include a conveying mechanism for moving earth materials excavated by the buckets to a location adjacent the excavator for removal. The bucket wheel is comprised of a circular frame 16, rotatably mounted at the end of the boom. The wheel is provided with buckets 18 having teeth 20 extending substantially outwardly from the periphery of the bucket for severing earth material as the bucket wheel is brought into a position for contacting the face of an exposed earth formation. The bucket is pivotally attached to the wheel at pivot 22. A jarring mechanism 24 is shown positioned between the lower back edge of the bucket and the bucket wheel frame. The jarring mechanism is pivotally connected at each end respectively to the bucket and frame. A tension spring 26 is connected between the upper side ofthe bucket and the wheel frame.

Referring next to FIG. 2 of the drawings, the mechanical jarring mechanism 24 is shown in greater detail. The mechanism is comprised of a cylindrical housing 27, which is closed at one end 25, and which has an opening 28 in its oppositc end communicating the outside of the housing with an has a shoulder 31, which serves as a hammer in the jarring mechanism. A mandrel 32 extends into the open end of the housing, and has an eye-33) in its outer end for connecting the device with the bucket. A shoulder 34 on the mandrel has an inwardly facing surface 35 which forms the anvil for the jar ring mechanism. The inner end of the mandrel has an enlarged portion 36. An annular shoulder 37 in the bore 29, forms a small diametered bore'38 in the center of the housing. A follower member 39 is positioned within the bore of the housing between the shoulder 37 and the closed end of the housing. A compression spring 41 is positioned between the follower member and such closed end 25 of the housing andnormally maintains an outer curved end 42 of the follower member against the shoulder 37. A trip pin 44 is positioned in the bore 29 between the enlarged end 36 of the mandrel and an outerbeveled edge 46 of the shoulder 37. Another compression spring 47 is positioned between shoulder 37 and an oblique shoulder 48 formed on the trip pin 44. The trip pin has a small diameter end portion 49 shown in FIG. 2 engaging the outer curved end 42 of the follower member. The oblique shoulder 48 on the trip pin forms a bias, so that normally the spring 47 is more compressed on one side and thereby holds the trip pin at an angle with respect to the small diametered bore 38 in the housing. This prevents alignment of the small end 49 of the pin and with a recess 51 in the curved end of the follower member 39. A conical shoulder 52 on the trippin connects the small end 49 with .an enlarged intermediate portion of the trip pin. The conical shoulder 52 forms a cam'surfac'e for engaging the beveled edge 46 of the annular shoulder 37.

FIG. 3 of the drawings shows the jarring mechanism of FIG. 2 inits operated condition. When an inwardly directed force is applied to the mandrel 32 of the jarring mechanism, the mandrel moves from left to right'as shown in FIG. 3. Such force is thereby transmitted through the mandrel and trip pin 44 to the follower member 39. The follower member 39 moves toward the closed end of the housing compressing the spring 41. At the same time, the spring 47, concentrically arranged about the trip pin 44 is also compressed between the oblique shoulder 48 on the pin and the shoulder 37 in the housing. Such movement continues until the cam surface 52 on the trip pin 44 engages the beveled edge 46 of the shoulder 37, whereupon the pin 44 is moved toward the center of the small diametered bore 38. Such centralizing of pin 44 aligns the small end 49 of the pin with the recess 51 in the follower member 39, whereupon the pin 44 plunges into the recess 51. The force on the mandrel, resisting the applied force, is suddenly released to accelerate the anvil into contact with the hammer 31. This in turn imparts a jarring impact to the man- I drel, which is shown in FIG. I as attached to the lower end of the bucket housing. Thus the jarring impact is transmitted to the teeth on the bucket for breaking hard materials being excavated.

FIG. 4 shows an alternative embodiment of a jarring mechanism, which operates on a hydraulic principle. The hydraulic system includes a mandrel 56 having an enlarged outer end which is formed in the shape of an eye 57 for attachment to the bucket housing. The'inner end of the mandrel 56 is sized for reception within the interior bore 58 ofa housing 59. The housing has a closed inner end 61 and an eye member 62 attached to the housing to permit connection of the housing to the bucket wheel. A shoulder 63 on the outer interior bore 29 in the housing. The open end of the housing end of the housing partially closes the outer end. A bore 64 in the outer end ofthe housing is provided with an O-ring seal 66 to provide afluid seal at the outer end of the housing, which in turn forms a hydraulic chamber in the housing between the seal and the closed end 61. The bore 58 of the housing has a shoulder portion 67 formed therein to provide a small diameter bore 68 within the housing. The mandrel has an enlarged portion on its inner end which forms a piston 69. The piston is sized in diameter to provide a restricted fluid flow path 71 between the small diameter bore 68 and the exterior surface of the piston 69 which permits a controlled rate of fluid flow between the piston-and shoulder 67. Passageways 72 are formed longitudinally through the piston 69 and communicate its opposite ends. Check valves 73 are positioned in each of the passageways72. The check valves 73 permit fluid flow through the passage in an inward direction (left to right). but prevent flow in an outward direction. A compression spring 74 is positioned between the inner end of the piston and the closed end,6l ofthe housing.

The hydraulic apparatus of FIG. 4 is operated as follows: A load of sufficient magnitude when imparted to the outer end of the mandrel causes .the piston to move inwardly within the hydraulic chamber which is filled with a hydraulic fluid. In order for the piston to move-inwardly, fluid must flow from the inner side of the piston through the restricted fluid flow path 71 between the piston and the shoulder to the outer side of the piston. This restricted passage of fluid permits a controlled and relatively slow rate of movement of the piston and mandrel inwardly. Upon moving a predetermined distance, the piston 69 enters the large diametered portion of the housing bore between the shoulder 67 and the closed end 61 of the housing, whereupon the movement of the piston is permitted to accelerate. This in turn causes the mandrel to move inwardly at a rapid rate, so that an anvil surface 76 on the enlarged portion of the mandrel jarringly engages the upper hammerend 77 of the housing. Such jarring impact is transmitted through the bucket to teeth on the bucket.

The jarring devices described in conjunction with FIGS. 2,-

tion of the device with the bucket and wheel will also operate the mechanism. Since the bucket is pivotally attached at its upper end to the bucket wheel, the lower end of the bucket is permitted to move inwardly and outwardly relative to the bucket wheel, thus permitting relative movement between the mandrel and housing of the jarring mechanism. In the normal operation of the bucket, the load encountered by the bucket in excavating earth materials is not sufficient to move the jarring mechanism to its operative condition. Therefore, under normal conditions the jarring mechanism does not operate. However, when the bucket engages material which is harder than the substance normally encountered, the load on the bucket can be sufficiently great, for a period of time. to move the. mandrel in the jarring mechanism an adequate distance within the housing to trip the jarring mechanism. In the apparatus shown in FIGS. 2 and 3, this is accomplished when the mandrel moves to an extent that the trip pin 44, which is en gaged with the mandrel, moves its camrning surface 52 into engagement with the-beveled edge 46 on the shoulder 37 to align the small end 49 of the pin 44 with the recess 51 in the follower member 39. When this happens, the force holding the housing against forward movement, which is transmitted from the mandrel to the housing through the follower member, is suddenly released, permitting the housing to accelerate rapidly in an opposite direction. This brings the hammer surface 31' on the housing into engagement with the anvil surface 35 on them'andrel to impart a jarring force to the mandrel. This jarring force is transmitted to the bucket to provide a jarring impact to the hard material in the earth being excavated.

After the jar mechanism is operated, the bucket moves with the rotating wheel to a position for emptying its contents wherein the weight of the bucket and tension spring 26 return the bucket to its normal position which in-turn resets the jar mechanism for subsequent operation. Appropriate stop members on the wheel limit the movement of the bucketwhen it ferred from the high pressure side of the piston to the low 1 pressure side through the restricted fluid flow path 71. When the piston exits into the large diametered portion of the housing bore, hydraulic fluid rapidly bypasses the piston 69 to permit the housing to accelerate rapidly in the opposite direction and impact the hammer 77 on the anvil 76.

Subsequent to the operation of the jarring mechanism, the bucket moves past'the restriction within the excavated material, so that the loadis no longer applied. At this point, the jarring mechanism is reset by the application of resetting forces to the jarring mechanism. Such resetting forces. are provided by the spring 74, which is located in the hydraulic mechanism between the piston 69 and the closed end 61 of the housing. in the mechanical jar restoring forces are provided by spring 41 between the follower member 39 and the closed end 25 of the housing, and spring 47 located between the oblique shoulder 48 on the trip pin and shoulder 37 in the housing bore. In addition, the spring 26 located between the upper end of the bucket and the bucket wheel also applies a restoring force to the jar in that it forces the mandrel in a direction away from the housing. In the hydraulic jar of FIG. 4, the passageways 72 in the piston 69, while preventing fluid flow during the jarring operation, permit fluid'flow during restoring movement of the mandrel to permit rapid movement of the piston 69 back into the small diameter bore 68 ofthe housing.

Referring next to FIG. 5 of the drawings, in a different embodiment of the invention, a jarring mechanism is connected directly to the tooth on the bucket 18. The jarring mechanism can be either mechanical or hydraulic and similar to those described above. For the sake of simplicity, only one such arrangement is shown, that being the mechanical jarring system as discussed with respect to FIGS. 2 and 3. In the operation of the apparatus in FIG. 5, the bucket is brought into contact with the earth materials being excavated. During normal excavating operations, the load imposed upon the tooth, which is attached to the upper end of the mandrel 32, is not sufficient to depress the mechanism to the extent that the jar is tripped. However, when the bucket tooth encounters an exceptionally hard surface, the mandrel is depressed within the housing to a point where the cam surface 52 on the trip pin 44 engages the beveled edge 46on shoulder 37 within the housing. This in turn aligns the small end 49 of the pin with the recess 51 in the follower member 39. Alignment of the pin and recess trips the mechanism thereby causing the jarring action as described above with respect to FIGS. 2 and 3. This jarring action is imparted to the tooth and to the material being excavated for breaking up the material and. permitting the bucket 18 to move on through the material.

FIG. 6 shows an arrangement of a bucket having two sets of teeth mounted thereon. The first set of teeth is comprised ofa tooth 81 extending upwardly from a mandrel 80 which is movably mounted' within a housing 82. The tooth 81 is held in an extended position by means of a compression spring 83 positioned between the enlarged lower end '84 of the mandrel and the bottom of the housing 82. The tooth 81 is constructed of a material such as tungsten carbide which prevents excep tional wear when contacted with abrasive material, such as bituminous tar sands. The second set of teeth are arranged on the bucket so that they are recessed downwardly from the movable teeth. These recessed teeth 86 are fixedly mounted on the bucket and preferably constructed of a tough, hard,

steel material. During normal excavating operations, the upwardly extending teeth 8] engage the material to be excavated before the recessed teeth, and thereby carry the load of normal excavating operations. However, upon encountering a harder than normal substance, the teeth 81 are permitted to recess inwardly into the housing by forcing the spring 83 to compress. The movable teeth 81 thus recess downwardly below the stationary teeth 86 so that the stationary teeth carry the excavating load during a situation where harder than normal substances are encountered in the excavating operation. This prevents the more brittle abrasive resistant teeth 81 from being broken when such hard substances are encounteredwithin the earth material. I

While the excavating apparatus disclosed herein has been described in conjunction with a bucket wheel excavator, it is readilyseen that such devices would have application to other types of earth handling equipment. In addition. while particular embodiments of the present invention have been shown and described, it isapparent that changes and modifications may be made without departing from this invention in its broader aspects and therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope ofthis invention.

lelaim:

1. In an apparatus for exeavatingearth materials and having material collecting means, the improvement comprising:

materials contacting members on said collecting means:

means associated with said collecting means for moving said collecting means and contacting members into contact with the earth materials being excavated with a first force; and selectively operable means for impacting said contact members against the earth materials with a force greater than the first force, said material collecting means being pivotally assembled on a frame and said selective operable means being mounted between said frame and said collecting means.

2.-ln an apparatus for excavating earth materials and having material collecting means, the improvement comprising: materials contacting members on said collecting means; means associated with said collecting means for moving said collecting means and contacting members into contact with the earth materials being excavated with'a first force; and selectively operable means for. impacting said contacting members against the earth materials with a force greater than the first force, said selectively operable means being comprised of: first and second telescoping members; releasable means for resisting relative movement'between said telescoping members; and means responsive to a load applied to one of said telescoping members for releasing said resisting means.

3 in an apparatus for excavating earth materials with means for contacting the materials to be excavated, which means comprises: a'first contacting member having physical wear properties which correspond to the nature of a first material to be excavated; a second contacting member having physical wearproperties which correspond to the nature of a second material to be excavated; one of said members being movable relative to the other of said members; and means responsive to a load imparted to said one of said members for moving said one of said members relative to said other of said members so that said other of said members is permitted to extend beyond the point of contact of said one of said members and the material to be excavated.

4. The apparatus of claim 3 wherein said one of said members is mounted on resilient means arranged to permit movement of said one of said members in response to a predetermined load applied to said one of said members.

5. In an apparatus for excavating earth materials. bucket means mounted on a rotatable frame, teeth mounted on said bucket means, at least one of said teeth being arranged to im part ajarring blow to thematerial being excavated and including: a housing mounted on said bucket and having a bore therein; a mandrel having one end extending through one end of said housing and connected at its other end to said one of said teeth, the other end of saidhousing being closed; means 74 between said one end of said mandrel and said other end of said housing forresisting movement of said mandrel; and means responsive to the resisted movement of said mandrel a predetermined distance for releasing said resisting means whereupon said one end of said housing is brought intojarring contact with said at least one of said teeth.

6. The apparatus ofclaimand further including means for adjusting the resisting means to vary the force necessary'to move said mandrel said predetermined distance.

7. The apparatus of claim 5 wherein said resisting means ineludes a release member positioned near the closed end of said housing and having a recess therein facing said one end of said housing, shoulder means in said bore between said release member and said one end of said housing and a shouldered pin member positioned between said one end of said mandrel and the recessed end of said release member when said mandrel is extended relative to said housing, said shouldered pin being aligned with said recess when the. shoulder on said pin is moved into eontactlwith said shoulder means in said bore to permit said pin to move into said recess, said alignment of said pin and recess permitting relatively unresisted movement of said mandrel relative to said housing.

8. In an apparatus for excavating earth materials and having collecting means, the improvement comprising: first materials contacting means fixedly mounted on said collecting means and extending outwardly therefrom; second materials contacting means movably mounted on said collecting means and extending outwardly therefrom a greater distance than said first materials 'contacting'r'neans; and means responsive to a load imparted to said second contacting means for permitting said second contacting means to move inwardly a distance greater than the distance said second contacting means normally extends outwurdly beyond said first contacting means. 

